Method and an apparatus for separating overlapping objects advanced on a conveyor

ABSTRACT

The disclosure relates to a method and an apparatus for separating overlapping objects ( 3 ) advanced on a conveyer. The conveyer is divided into two individually driven paths, a first ( 1 ) and a second ( 2 ). The paths ( 1, 2 ) each have a bending roller ( 5, 6 ) lying adjacent one another and being interconnected and moveable in the horizontal plane. When separation is to take place, the conveyer paths ( 1, 2 ) and the bending rollers ( 5, 6 ) are advanced forwards at the same speed. Thereafter, the bending rollers ( 5, 6 ) and the second conveyer belt ( 2 ) are accelerated momentarily whereafter the bending rollers ( 5, 6 ) return to the original speed. The The disclosure relates to a method and an apparatus for separating overlapping objects ( 3 ) advanced on a conveyer. The conveyer is divided into two individually driven paths, a first ( 1 ) and a second ( 2 ). The paths ( 1, 2 ) each have a bending roller ( 5, 6 ) lying adjacent one another and being interconnected and moveable in the horizontal plane. When separation is to take place, the conveyer paths ( 1, 2 ) and the bending rollers ( 5, 6 ) are advanced forwards at the same speed. Thereafter, the bending rollers ( 5, 6 ) and the second conveyer belt ( 2 ) are accelerated momentarily whereafter the bending rollers ( 5, 6 ) return to the original speed. The second conveyer belt ( 2 ) maintains a higher speed until such time as a requisite separation space is realised. Finally, the second conveyer belt ( 2 ) returns to the original speed, at the same time as the bending rollers ( 5, 6 ) move backwards.

TECHNICAL FIELD

The present invention relates to a method of separating overlapping objects advanced on a conveyer, the conveyer being divided into two individually driven paths, a first and a second, each with a bending roller lying adjacent one another, the bending rollers being interconnected and moveable in the horizontal plane. The present invention also relates to an apparatus for carrying the method into effect.

BACKGROUND ART

When paper sheets or similar, planar objects are conveyed on a conveyer, they normally overlap one another to a greater or lesser extent. By conveying planar or flat-laid objects overlapping, the conveyer may be advanced at relatively reasonable speed. This method of conveying also saves space. How much the objects may overlap one another depends on the material from which the objects are manufactured and also the thickness of the objects themselves.

In all advancement of objects on a conveyer, it is necessary or desirable to separate or group the flow of objects. As regards individual objects which are advanced without overlapping, this is a relatively simple process.

When the intention is to carry out the separation in a continuous process, this becomes slightly more complicated. Swedish Patent Specification SE 0101914-0 describes an apparatus for the continuous marshalling or grouping of objects such as packaging containers. The apparatus has a conveyer which is divided with mutually adjacent bending rollers which are moveable in the horizontal plane, together with a stop member. The stop member may also move up or down between the bending rollers.

As regards overlapping objects, this principle is not applicable. Hitherto, use has been made of specific knives or lances which have been inserted obliquely from beneath in between the overlapping objects at that point where it is intended to separate the flow of objects. This method is not continuous, since it is necessary to stop the conveyer in order to realise an actual separation of the flow of objects. Moreover, this method suffers from the drawback that the knife or lance which is inserted may damage the surface of the objects lying most proximal the point of separation.

In particular as regards sheets for the manufacture of single-use disposable packages for foods, it is important that the surface of the sheet is not damaged. The sheet normally consists of a core of paper or paperboard to which are laminated different layers of plastic, and possibly also aluminium foil. The sheets may be unglued, totally planar or alternatively glued to form so-called blanks which are flat-laid.

When these sheets are advanced as a flow, it is occasionally necessary to separate the flow. This may, for example, be when the intention is to unite two flows to form a single flow or if the intention is to divide up a flow into two or more. Separation or grouping of a flow of sheets may also be employed when the intention is to pack a given number of sheets in a carton or the like.

OBJECTS OF THE INVENTION

One object of the present invention is to realise a method of separating. overlapping objects on a conveyer where there is no risk of damaging the surface of the objects.

A further object of the present invention is that the separation or grouping may be carried out continuously, since most processes presuppose an increasing speed in order to carry out different operational phases.

Solution

These and other objects have been attained according to the present invention in that the method of the type described by way of introduction has been given the characterising features that, when separation is to take place, the conveyer paths and the bending rollers move forwards at the same speed, that the speed of the bending rollers and the speed of the second conveyer path are thereafter accelerated momentarily forwards, whereafter the bending rollers reassume the original speed while the second conveyer path maintains a higher speed until such time as the requisite separation spacing has been achieved, and finally the second conveyer path returns to the original speed at the same time as the bending rollers move backwards.

Preferred embodiments of the present invention have further been given the characterising features as set forth in the appended subclaims.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

One preferred embodiment of the present invention will now be described in greater detail hereinbelow, with reference to the accompanying Drawing. In the accompanying Drawing:

FIG. 1 is a schematic illustration of an apparatus for carrying the method according to the present invention into effect.

DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 1 shows an apparatus which consists of two driven, endless conveyer belts a first 1 and a second 2. The apparatus is intended for planar or flat-laid objects 3 such as paper sheets or the like. The objects 3 are advanced through the apparatus as shown by means of an arrow 4 in FIG. 1. The objects 3 arrive in an overlapping flow. How large the overlap is depends upon the material of the objects 3 and on their thickness.

The two endless conveyer belts 1, 2 have a number of bending rollers. Two of the bending rollers 5, 6 are placed adjacent one another and in close association with the objects 3. Both of these bending rollers 5, 6 are secured on a joint bracket 7. This bracket 7 is further secured on a linear unit or similar device (not shown). For example, the linear unit may be servo-controlled, frequency-controlled or pneumatically controlled. As a result of the linear unit, the bracket 7 with the two bending rollers 5, 6 may move reciprocally in the horizontal plane, parallel with the upper side of the conveyer belts 1, 2 as shown in FIG. 1 by means of a double headed arrow 8.

Both of the conveyer belts 1, 2 also each display a bending roller 9, 10 which terminates that part of the belts 1, 2 on which the objects 3 rest. Thus, the objects 3 are advanced on the first conveyer belt 1 between the bending rollers 9 and 5, whereafter they pass over to the second conveyer belt 2, between the bending rollers 6 and 10. The upper side or part of the first conveyer belt 1 is preferably located on a level which lies above the upper side or part of the second conveyer belt 2.

Each conveyer belt 1, 2 moreover possesses a number of additional bending rollers. Two of these 11, 12 are also interconnected to a joint bracket 13. The two bending rollers 11, 12 are also moveable in the horizontal plane. The remaining bending rollers which are disposed along the two conveyer belts 1, 2 are fixed.

The two conveyer belts 1, 2 are both driven individually and independently of each other. The driving means may be disposed on the bending rollers 9, 10 or on one of the other bending rollers where the driving operation does not disrupt or come into conflict with the method according to the present invention.

The apparatus is further provided with a nip roller 14 which is pressure- or spring-biased or which acts by its own weight. The nip roller 14 is placed in register with the bending roller 5 on the first conveyer belt 1. The nip roller 14 is secured on the same bracket 7 as the bending rollers 5 and 6.

When no separation takes place, the objects 3 enter the apparatus according to the invention from another conveyer belt or direct from a machine (not shown). The objects 3 are advanced on the first conveyer belt 1 and, once they have passed between the bending roller 5 and the nip roller 14, they fall down onto the second conveyer belt 2. Thereafter, the objects 3 depart from the apparatus and possibly continue on another conveyer belt (not shown). The two conveyer belts 1, 2 move at the same speed.

When a separation or grouping of the objects 3 is to take place, the linear unit with the bracket 7 and the two bending rollers 5 and 6 begins to move forwards in the direction of movement of the conveyer belts 1, 2. At the same time, the bracket 13 with the two bending rollers 11, 12 moves in the opposite direction. The linear unit has the same speed as the two conveyer belts 1, 2.

When the point 3 in which it is intended to effect separation is located between the bending roller 5 and the nip roller 14, a momentary acceleration takes place of the speed of the second conveyer belt 2 and the speed of the linear unit. The linear unit accelerates forwards a distance which corresponds to 25-75% of the length of an object 3. The acceleration distance depends upon the material of the objects 3. If the objects 3 are rigid, a shorter distance is required. The sloppier the material from which the objects 3 are manufactured, the longer will be the requisite distance.

Thereafter, the linear unit returns to the original speed, i.e. the same speed as that of the first conveyer belt 1. On the acceleration of the linear unit, a jerk occurs which entrains the objects 3 which are not held between the bending roller 5 and the nip roller 14. Those objects 3 which are held by the bending roller 5 and the nip roller 14 will fasten in this position as long as the linear unit moves forwards.

The second conveyer belt 2 continues at the increased speed until such time as there is sufficiently great space between two objects 3. This space may vary from a few millimetres to an optional number of metres, depending on what the intention is with the separation. The space may be defined as a distance where there is no overlap. If a space is desired so as to be able to package the objects 3, it may be sufficient to provide a space of a few millimetres. If the intention is to unite objects 3 from two parallel conveyer belts, a space of a few metres may be needed so that the second conveyer belt 2 is emptied of objects 3. How much faster the second conveyer belt 2 must move also depends on how great the space is intended to be created.

Once a sufficient space has been realised, the second conveyer belt 2 returns to the original speed, i.e. the same speed as the first conveyer belt 1 and the linear unit. At the same time, the linear unit reverses and reverts to its original position. Then, the bending rollers 5, 6 on the bracket 7 will move backwards in the direction of movement of the conveyer belts 1, 2 at the same time as the bracket 13 with the bending rollers 11, 12 moves forwards. The apparatus is thereafter ready to commence a new cycle of separation according to the method according to the present invention.

As will have been apparent from the foregoing description, the present invention realises a method and an apparatus which make it possible to separate or group a flow of overlapping objects advanced on a conveyer path. The separation may take place continuously and in such a manner that there is no risk that the objects be damaged or disrupted. 

1. A method of separating overlapping objects (3) advanced on a conveyer, the conveyer being divided into two individually driven paths, a first (1) and a second (2) each having a bending roller (5, 6) lying adjacent one another, said bending rollers (5, 6) being interconnected and moveable in the horizontal plane, characterised in that when separation is to take place, the conveyer paths (1, 2) and the bending rollers (5, 6) move forwards at the same speed, that the speed of the bending rollers (5, 6) and the speed of the second conveyer belt (2) are thereafter accelerated momentarily forwards, whereafter the bending rollers (5, 6) return to the original speed, while the second conveyer belt (2) maintains a higher speed until such time as a requisite separation space has been realised, and finally the second conveyer belt (2) returns to the original speed at the same time as the bending rollers (5, 6) move backwards.
 2. The method as claimed in claim 1, characterised in that the second conveyer belt (2) is accelerated over a distance which corresponds to 25-75% of the length of an object (3).
 3. The method as claimed in claim 1, characterised in that the bending rollers (5, 6) are driven by a linear unit.
 4. An apparatus for separating overlapping objects (3) advanced on a conveyer, the conveyer being divided into two individually driven paths, a first (1) and a second (2) each with a bending roller (5, 6) lying adjacent one another, said bending rollers (5, 6) being interconnected and moveable in the horizontal plane, characterised in that the bending rollers (5, 6) are secured on a bracket (7), said bracket (7) being secured on a driven linear unit.
 5. The apparatus as claimed in claim 4, characterised in that there is also secured on the bracket (7) a nip roller (14), said nip roller (14) being placed in register with the bending roller (5).
 6. The apparatus as claimed in claim 4, characterised in that the objects (3) are advanced on the first conveyer path (1) between a bending roller (9) and the bending roller (5), and that they are advanced on the second conveyer path (2) between the bending roller (6) and a bending roller (10).
 7. The apparatus as claimed in claim 6, characterised in that the first conveyer path (1) between the bending rollers (9) and (5) is disposed on a level which lies above the level of the second conveyer path (2) between the bending rollers (6) and (10). 